1. Field of the Invention
The present invention relates generally to a device for reducing or absorbing vibration or shock occurring during the operation of the reader head in reading data from for example a compact disc in a CD-ROM and in particular to a shock absorbing device which comprises counterweight means to provide a more balanced distribution of weight in the reading mechanism so as to reduce the shock and vibration caused by the operation of the moving parts of the reading mechanism.
2. Related Arts
CD-ROMs have been widely used in computer systems as mass data storage. The CD-ROMs comprise an optic reader device which has a reader head movable inside the CD-ROM to be positionable with respect to a compact disc for accessing data on the compact disc. To correctly read data, the positioning of the reader head has to be precise so that vibration and/shock occurring during the operation of the reader head has to be alleviated or even eliminated.
A conventional design of the reading mechanism of the CD-ROMs which is used to move the reader head is illustrated in FIG. 6 of the attached drawings. The conventional reading mechanism comprises a driving motor A for coupling to and driving the compact disc and the driving motor A is usually mounted at one end side of the reading mechanism. A reader head B is guided by two opposite guide rails C and C' to be movable with respect to a compact disc received in the CD-ROM.
In the conventional design, the reading mechanism is directly fixed to the CD-ROM by means of for example bolts or screws. No means for buffering vibration or absorbing shock caused in the operation of the reading mechanism is provided so that the vibration or shock so caused may negatively affect the positioning and/or reading operation of the reader head B.
Further, in the conventional design, the driving motor A has to be arranged at one end side of the reading mechanism which causes an imbalance distribution of weight in the reading mechanism for most of the remaining parts of the reading mechanism is made of light-weighted materials for the sake of reducing cost. When the reader head B is moved in the direction toward the driving motor A, the weight imbalance problem may become more serious and vibration or shock caused thereby may be more significant.
To solve such problems, a variety of techniques have been developed, such as Taiwan patent publication No. 307003 which discloses a compensation circuit for reducing negative effect caused by the vibration and/or shock. However, such a circuit is useless in correcting problem caused by imbalance of weight.
It is thus desirable to provide a shock absorbing device adapted to be incorporated in a CD-ROM reading mechanism to both effectively absorb vibration/shock and provide a more balanced weight distribution in the reading mechanism.